The average obese woman gets only one hour of vigorous exercise each year, and obese men get less than four, according to a new study.

Participants in the study, published in Mayo Clinic Proceedings, had accelerometers that tracked their movements and provided data about how much they exercised and at what intensity. Vigorous exercise was defined as fat-burning activities like jogging, though one academic not related to the study cautioned that “vigorous” is relative to an individual’s fitness level. For some severely obese people, walking could be a vigorous activity.

The federal recommendation for exercise is at least 2.5 hours of moderate-intensity aerobic exercise every week, and research shows that just 30 minutes of exercise five days a week will help maintain one’s weight.